1. Field of the Invention
The present invention relates to an existing pipe cut-off method, and a valve insertion method for inserting a valve in a line without stopping passage of water or fluid, etc.
2. Description of Prior Arts
Conventionally, a valve insertion method for inserting a valve in a line without stopping passage of water, by which an existing pipe is cut off without stopping passage of water and a valve is inserted into the cut-off portion of the existing pipe in a line including the existing pipe, has been already publicly known.
FIG. 72 shows a sketch of a conventional method disclosed in Japanese Laid-Open Patent Publication Nos. 44167 of 1980, 83690 of 1981, 120886 of 1981, and 47089 of 1982.
The method illustrated in the drawing is such that cutting equipment 500 is fixed at an existing pipe 1, the cutting equipment 500 and existing pipe 1 are enclosed and sealed up by a seal-up housing 501, and the left and right blades 502 are rotated along the cutting equipment 500 in order to cut off the existing pipe 1. Thereafter, a valve is inserted into a line 1A instead of a cut-off section 10 of the existing pipe 1 by opening and closing an operation sluice valve 503. In the prior art, since the cutting equipment 500 is accommodated in the seal-up housing 501, the seal-up housing 501 is made large-scaled to resultantly expand the digging area, etc.
FIG. 73 shows a sketch of a prior method disclosed in U.S. Pat. No. 5,611,365 and International Laid-Open WO 97/31207.
With the method illustrated in the drawing, an existing pipe 1 is enclosed and sealed up by a seal-up housing 600, a cutting tool 602 is fixed at and attached to the tip end of a gate valve 601 installed at the seal-up housing 600, and the gate valve 601 is turned together with the seal-up housing 600, wherein an existing pipe 1 is cut off by the cutting tool 602. According to the prior arts, since the cutting tool 602 is turned by rotations of the seal-up housing 600, it is not necessary that the seal-up mechanism for turning the cutting tool 602 is provided in a seal-up housing 600. Therefore, the seal-up housing 600 can be small-sized.
However, with such conventional cut-off methods, a chip-like cutter 602 bites an existing pipe 1. Therefore, in a housing of cutting into an existing pipe 1 made of cast iron or steel, the seal-up housing 600 must be turned many times, wherein it takes much time to cut off. Furthermore, there is a fear that rubber packing to seal between the seal-up housing 600 and existing pipe 1 is damaged.
FIG. 74 shows a sketch of a conventional cut-off method disclosed in U.S. Pat. Nos. 3,650,547, 3,703,906, and 3,735,775.
With the prior art shown in the drawing, an existing pipe 1 is enclosed and sealed up by a seal-up housing 700, and after a cutting wheel 701 attached to the seal-up housing 700 is caused to bite the existing pipe 1 by a lead screw 702, the cutting wheel 701 is turned together with the seal-up housing 700, whereby the existing tube 1 is cut off.
With the cutting method, since the cutting wheel 701 has a smooth outer circumferential part, it is impossible to cut off an existing pipe 1 made of cast iron and steel.
FIG. 75(a) and FIG. 75(b) show views of a conventional method for inserting a valve in a line without stopping passage of water, which is disclosed in U.S. Pat. No. 3,948,282.
With the conventional method shown in these drawings, an existing pipe 1 shown in FIG. 75(a) is enclosed and sealed up by a seal-up housing 800. Subsequently, an operation sluice valve 801 is attached to the seal-up housing 800. Thereafter, a circular hole 803 is drilled by using a hole saw 802 in compliance with an already known method. After the drilling is completed, as shown in FIG. 75(b), a valve body 804 which is fitted into the drilled circular hole 803 is inserted therein.
With the conventional valve inserting method, since the hole 803 which has roughly the same diameter as the inner diameter of the existing pipe 1 is provided, the seal-up housing 800 shown in FIG. 75(a) is made longer in the axial direction S and is made large-sized.
Furthermore, with the conventional inserting method, since hydraulic pressure is given to the valve body 804 shown in FIG. 75(b) with respect to a large area equivalent to the circular hole, the diameter of the valve rod 806 is unavoidably made large.
Still furthermore, with the conventional inserting method, the circumferential edge 805 of the hole 803 at the existing pipe 1 is made thin, and pressure resulting from the valve body 804 is applied to the circumferential edge 805, wherein the existing pipe 1 is liable to be broken.
FIG. 76(a) and FIG. 76(b) show the outline of a conventional valve insertion method for inserting a valve in a line without stopping passage of water, which was disclosed in U.S. Pat. No. 4,516,598.
In the prior art shown in these drawings, the existing pipe 1 in FIG. 76(a) is enclosed and sealed up by an seal-up housing 800. At this time, a hole saw 802 and a valve body 804 are accommodated in advance in the seal-up housing 800. Thereafter, a circular hole is drilled at the existing pipe 1 by the hole saw 802. After the drilling is completed, the seal-up housing 800 is turned as shown by the arrow 850 in FIG. 76(a). After that, a valve body 804 is inserted into the circular hole 803 in FIG. 76(b).
FIG. 77 shows the outline of a conventional valve insertion method for inserting a valve in a line without stopping passage of water, which was disclosed in U.S. Pat. No. 1,989,768.
In the prior art shown in this drawing, the existing pipe 1 in FIG. 77 is enclosed and sealed up by a seal-up housing 501. At this time, cutting equipment 500 and a sluice valve 510 are accommodated in advance in the seal-up housing 501. After the cutting equipment 500 having a blade 502 cuts off and removes the existing pipe 1, the sluice valve is inserted instead of the cutting equipment 500.
The prior arts shown in FIG. 76(a), 76(b), and FIG. 77 are able to quickly insert a valve after the cutting is completed. But with the prior arts shown in FIG. 76(a), 76(b), and FIG. 77, since it is necessary to accommodate a hole saw 802 or cutting equipment 500, the size of which is equivalent to that of the valves 804 and 510 to be inserted, in the seal-up housing 800 or 501, the seal-up housings 800 and 501 are obliged to be large-scaled.
The present invention has been developed to solve the problems inherent to the prior arts, and it is therefore a major object of the invention to provide an existing pipe cut-off method by which the existing pipe made of cast iron or steel can be cut off without causing its seal-up housing to turn many times.
It is another object of the invention to provide a method for inserting a valve in a line without stopping passage of water, in which the abovementioned method is employed.
It is still another object of the invention to provide a piping structure in which an existing pipe is scarcely damaged, an existing pipe slitting method by which the existing pipe can be slit to such a shape as the existing pipe is scarcely damaged, and a method for inserting a valve in a line without stopping passage of fluid.
In order to achieve the abovementioned main object, in a cut-off method according to the invention, a cutting tool, which is fixed at a rotatably supported cutter shaft and is provided with a plurality of blades, is accommodated in a seal-up housing in a state where the cutting tool is attached to the abovementioned seal-up housing while enclosing, in an airtight state, a part of an existing pipe by the abovementioned seal-up housing which is divided into plural sections in the circumferential direction of the existing pipe.
Subsequently, the abovementioned cutting tool is fed roughly in the cross direction of the abovementioned existing pipe in a state of performing a slitting motion to slit the abovementioned existing pipe by rotations of the abovementioned cutting tool by causing the abovementioned cutting tool to rotate on the abovementioned cutter shaft by power of a prime mover, wherein the abovementioned cutting tool is caused to perform a feed motion with the abovementioned cutting tool turned in the abovementioned circumferential direction by causing at least a part of the abovementioned seal-up housing to turn in the abovementioned circumferential direction of the abovementioned existing pipe, and the abovementioned existing pipe is cut off by the abovementioned cutting tool.
According to the invention, since the existing pipe is slit by rotating the cutting tool on its cutter shaft, any existing pipe made of cast iron or steel is able to be easily cut off by turning the seal-up housing one to three times. Therefore, the cut-off time can be shortened, and there is no fear that rubber packing secured at the rotating and sliding portion is damaged.
In the invention, xe2x80x9cexisting pipexe2x80x9d means a pipe through which fluid such as water flows and is generally buried under the ground.
xe2x80x9cSeal-upxe2x80x9d does not mean xe2x80x9ccompletely sealedxe2x80x9d but means such a state where work can be carried out without stopping passage of water or fluid. Therefore, xe2x80x9cseal-up housingxe2x80x9d means a housing which has such a pressure resisting capacity, by which it can withstand the pressure of fluid flowing through the existing pipe, and has a sealing capacity to some degree.
Furthermore, xe2x80x9cenclosed and sealed up in an airtight statexe2x80x9d means such a sealed up state where work such as inserting a valve in a line after cut-off or slitting is not hindered, for example, wherein a water discharge port is provided at the seal-up housing and is made open during slitting of an existing pipe, and cutting chips may be discharged through the discharge port together with water.
Since a xe2x80x9ccutting toolxe2x80x9d used in the present cut-off method has a plurality of blades, the corresponding cutting tool does not include a cutting chip and a cutter wheel having a single continuous blade. As the xe2x80x9ccutting toolxe2x80x9d used in the cut-off method, a columnar cutting tool having a plurality of blades on its tip end and its outer circumferential surface may be used in addition to a diamond wheel and a metal slitting saw, etc.
Here in the specification, xe2x80x9cpillar shapexe2x80x9d means a conical trapezoidal shape in addition to a columnar shape, and includes such a shape, in which a conical shape is added to a column, and a conical shape. Furthermore, it may be of a short-pillar shape in comparison with the outer diameter of a cutting tool.
Furthermore, in a housing of slitting an existing pipe having mortar lining on its inner circumferential surface, it is preferable that a cutting tool having a plurality of blades made of an ultra-hard alloy, or a cutting tool, the blades of which are made of diamond grains, is used.
Furthermore, in the invention, xe2x80x9cslittingxe2x80x9d means slitting a part of a pipe wall by rotating a plurality of blades. On the other hand, xe2x80x9ccut-offxe2x80x9d means cutting off a pipe into two or more sections. Furthermore, xe2x80x9cslitting motionxe2x80x9d means causing a plurality of blades to rotate on the cutter shaft. On the other hand, xe2x80x9cfeeding motionxe2x80x9d means causing the abovementioned cutting tool to move to the position where a new part of the pipe wall can be progressively cut off or slit by the cutting tool.
In the invention, xe2x80x9cfeeding the cutting tool roughly in the cross direction of the existing pipe and causing the seal-up housing to turn in the circumferential direction of the existing pipexe2x80x9d means both housings, one of which is turning the seal-up housing after the cutting tool is fed roughly in the cross or diametrical direction of an existing pipe, and the other of which is turning the seal-up housing while feeding the cutting tool roughly in the cross or diametrical direction of an existing pipe.
It is possible to insert a valve into the cut-off position of the existing pipe in a line after the existing pipe is cut off by the cut-off method of the invention.
Furthermore, in the invention, xe2x80x9cinserting a valve (in a line)xe2x80x9d does not mean physically inserting a valve or valve body in a cut-open section of an existing pipe but means installing a valve, which can stop water or regulate the flow quantity in an existing line, in the corresponding line.
Herein, xe2x80x9cvalvexe2x80x9d means the entire valve, that is, valve assembly, including a valve body, valve housing, valve rod, etc.
Furthermore, xe2x80x9cvalve bodyxe2x80x9d means a member which clogs a flow passage, in the case of a sluice valve, it is generally called a gate, and in the case of a butterfly valve, it is a member which turns around the valve rod,
Still furthermore, xe2x80x9cvalve housingxe2x80x9d means a member which accommodates the valve body, regardless of its opened or closed state of the valve body.
In order to achieve the abovementioned other object of the invention, a piping structure according to the invention is provided with an existing pipe, a seal-up housing, a sluice valve body and a valve rod.
The abovementioned existing pipe has a slit groove obtained by notching the corresponding existing pipe in a range of approximately 180 degrees in the circumferential direction thereof.
The abovementioned seal-up housing is divided into plural sections in the circumferential direction of the abovementioned existing pipe and encloses and seals up the existing pipe in an airtight state.
The sluice valve body has rubber packing which is brought into contact with the inner circumferential surface of the existing pipe and a cut-off surface forming the abovementioned slit groove in the corresponding existing pipe in the open state (closed state). The sluice valve body moves in the diametrical direction of the abovementioned existing pipe in the seal-up housing and invades the existing pipe through the slit groove, wherein the abovementioned rubber packing stops a stream of fluid in the existing pipe.
The abovementioned valve rod causes the valve body to move roughly in the cross direction.
In a preferred embodiment of the invention, the slit groove is formed by slitting an existing pipe by the cutting tool.
Furthermore, in another preferred embodiment of the invention, the slit surface forming the abovementioned slit groove is formed so that the angle with respect to the surface of the existing pipe at the corresponding part is set in a range from 45 degrees through 90 degrees.
Furthermore, in still another preferred embodiment of the invention, both end portions of the abovementioned slit groove in the circumferential direction are made roughly U-shaped.
A piping structure according to the invention is completed by inserting a valve in a line, by a method for inserting a valve in a line without stopping passage of fluid according to the invention, after slitting an existing pipe by, for example, an existing pipe slitting method of the invention. Furthermore, xe2x80x9cwithout stopping passage of fluid (water)xe2x80x9d means that work is carried out without stopping a stream of fluid (for example, water) flowing in a line.
That is, in an existing pipe slitting method according to the invention, a cutting tool, which is rotatably supported on the axial line established roughly in the cross direction of an existing pipe and is provided with at plurality of blades on the tip end face and outer circumferential surface of the columnar portion thereof, is accommodated in a seal-up housing in a state where the cutting tool is attached to the abovementioned seal-up housing while enclosing, in an airtight state, a part of the abovementioned existing pipe by the abovementioned seal-up housing which is divided into plural sections in the circumferential direction of the existing pipe. Subsequently, the abovementioned cutting tool is fed roughly in the cross direction of the abovementioned existing pipe in a state of performing a slitting motion to slit the abovementioned existing pipe by rotations of the abovementioned cutting tool by causing the abovementioned cutting tool to rotate on the abovementioned axial line by power of a prime mover, wherein the abovementioned existing pipe is slit by the abovementioned cutting tool in a range of approximately 180 degrees in the circumferential direction thereof by causing the abovementioned cutting tool to perform a feed motion with the abovementioned cutting tool turned in the abovementioned circumferential direction by causing at least a part of the abovementioned seal-up housing to turn in the abovementioned circumferential direction of the abovementioned existing pipe.
After the existing pipe is slit in a range of approximately 180 degrees by the abovementioned cutting tool in conjunction with a slitting. method according to the invention, a valve is inserted in a line. The valve body of the valve invades the existing pipe through the slit groove, clogs the slit groove itself, and is pressure-fitted to the inner circumference of the existing pipe, thereby closing the abovementioned existing pipe.
According to the invention, a cutting tool, the axial line of which is set in the diametrical direction of an existing pipe, is fed in the circumferential direction of the existing pipe to slit the existing pipe like a deep groove. Therefore, since the peripheral edge portion of the slit groove at the existing pipe is not made thin, there is no fear that the existing pipe is damaged when a valve body is fitted in the abovementioned slit groove.
Furthermore, in the slitting method, xe2x80x9cslitting in a range of approximately 180 degrees in the circumferential directionxe2x80x9d means slitting through an existing pipe to such a degree that the valve body having a size approximate to the inner diameter of the existing pipe can be inserted thereinto through the slit groove.